Agricultural vehicles, such as tractors, combines, and trailers, as well as comparable vehicles that are used on soft ground, are often equipped with tires of large volume in order to achieve good land mobility, good traction properties, and adequate ground pressure. Traction and ground pressure are especially low when a low air pressure is set in the tire. As such, low tire pressure is preferred for field operations. However, with decreasing tire pressure, the pulling ability of the tires decreases, and tire wear and the resistance to rolling increase. In order to satisfy these conflicting demands, various tire-pressure regulating systems are used, as can be seen from DE 198 04 249 A1 or U.S. Pat. No. 5,647,927. With the aid of a tire-pressure regulating system, the air pressure in the tire can be adjusted optimally to the requirements of the particular work in which it is being used. The air pressure required to fill the tire using these tire-pressure regulating systems is supplied by a compressor, which feeds an air-pressure container.
Generally in order to generate a pressure that can be set, the space between the tire and the rim is filled with a gas, for example with air. Therefore, the pressure source is typically a compressor that sucks air in from the environment, compresses it, and directs it into the space formed by the tire and rim.
Furthermore, it is known in the art that an emergency system can be provided for vehicle tires, with which at least limited travel is possible even in the event of a tire blow out. Such an emergency systems typically consist of a hose arranged between the rim bed and the tire. In the event the tire blows out, travel on this hose is possible. Such an emergency tire system is known from GB2,258,195A, for example, which discloses a tire inflation system that includes means by which gas or air can be made available for inflating the tire. This emergency tire system is implemented in such a way that the tire pressure is kept essentially constant.
Adjusting tire pressure in the case of a large volume tires, as is common in agricultural vehicles, takes an undesirably long time, since a large volume of gas has to be moved into or out of the tire, and because only a limited gas flow can be directed through a valve on the tires, especially when traditional valves are provided.
Accordingly, there is a clear need in the art to provide a tire pressure adjustment system with which the above-mentioned problems can be overcome. In particular, by reducing the time period for changing the tire pressure.